Pressure cylinder unit and method



June 18, 1957 D H NEWHALL 2,796,229

RREssuRE CYLINDER UNIT AND METHOD Filed Aug. 15, 1952 i 4 sheets-sheet 1 oaa Haywood Zilvai June 18, 1957 D. H. NEwHALL 2,796,229

PRESSURE CYLINDER UNIT AND METHOD Filed Aug. 15. 1952 IES /O lle f/ 114' 13ofsa- 134 Ise- 4 Shee'ts-Sheet 2 June 18, 1957 D H, NEWHALL 2,796,229

PRESSURE CYLINDER UNIT AND METHOD Filed Aug. l5, 1952 4 Sheets-Sheet 3 /as Q04 aaa @Invezzoa'a- .ozald H'wooolemail,

.Hozzey June 18, 1957 D. H. NEWHALL 2,796,229

PRESSURE CYLINDER UNIT AND METHOD gi g 9i ll uowazeg;

United States Patent O 2,796,229 PRESSURE CYLINDER UNIT AND METHOD Donald H. Newhau, Walpole, Mass. v

Application August 15, 1952, Serial No. 304,564

9 claims. (ci. 251-61) The present invention Arelates to an improved pressure cylinder unit for containing lluid pressures and method of producing a measurable variation of wall diameters within the unit, and more specifically to a novel'construction and arrangement of a pressure cylinder unit comprising inside cylinder and sleeve cylinder elements and to a method of operating said unit to produce a controlled leakage or inltration of the fluid under pressure between the walls of the inside cylinder and sleeve cylinder elements for any pressure to which the unit may be subjected. v

Difficulty has been encountered in adapting pressure units for use with very high pressures and with pressures which may vary over a considerable range, to maintain a free sliding fit with a controlled rate of leakage oi the contained pressure medium .between the inside and :sleeve cylinder elements. As the pressure to which the unitis subjected is increased the amount of clearance required,

as measured by the difference in diameters between the opposed wall surfaces becomes very small, while at the same time the tendency of the cylinder walls to -bedistorted by the heavy pressure employed is greatly increased. Inability to overcome the mechanical diiliculties involved in containing very high pressures has heretofore seriously limited the usefulness of pressure units for high pressure work.

It is a principal object of the invention to provide a pressure cylinder unit or similar device containing a iluidmedium under high pressure which is adapted to be con- Itrolled in a novel manner to maintain the required amount of clearancebetween the opposed cylinder walls and a controlled rate of leakage of the contained lluid medium past the unit for any particular pressure to which the unit may be subjected. n

It is a further object of the invention to provide in a metallic pressure cylinder unit a novel method for controlling the degree of iniiltration of the contained loading pressure medium which may be permitted through the pressure cylinder unit over an extreme lrange of loading pressures. s

It is another object of the invention to provide in a metallic pressure cylinder unit or similar device a novel device for controlling within close limits which may approximate the nearest millionth of an inch the diameter of a cylinder wall against which the loading pressure is directed and thereby to control the amount and rate-of leakage or inltration of the loading pressure medium across the unit. p

More specically it isnan object of the invention to provide a simple at the same time eiective device for `controlling the relative wall diametersrof the inside adjustment independently of variations of loading pressure ice of the contained uid medium, and which is adapted at the same time to control the rate of leakage of the loading pressure medium through the unit.

It is another object of the invention to provide a novel and improved seal for sealing in the two sides of an annular cavity provided Vbetween. two superimposed cylinder elements for containing therein a lluid medium main tained under very high pressures. Y

In accordance with the invention it is proposed to subject at least one of the metallic cylinder elements of a pressure cylinder unit to a separate independently controlled radially directed pressure which produce a controlled adjustment oi. wall diameter Within the elastic Ilimits of the cylinder element, and which will further offset and correct to any desired extent within the elastic limits ofthe metal cylinders the tendency of the contained loading pressure to distort the cylinder Walls. Within the spirit and scope of the -invention the control pressure may be applied externally of the sleeve cylinder element ais a compressive force oiisetting and if so desired .reversing the tendency of the sleeve cylinder to expand under the loading pressure, or may alternatively be applied internally or axially against the inside cylinder element to expand the inside cylinder against the wall of the sleeve cylinder element. By asimple adjustment of the oisetting clearance control pressure the amount of the clearance between the inside and lsleeve cylinder walls is readily adjusted to produce the desired amount of leakage of the loading pressure through the pressure cylinder unit for any conditions of loading and exhaust pressures which may be encountered in the use of the unit. accordance with the invention it is contemplated 4that an externally applied, radially directed control pressure may be employed for effecting a very close adjustment of the internal diameter of a metallic sleeve cylinder having a small unobstructed central bore, as for example a lap.

Specific embodiments of the invention hereinafter more fully described and illustrated by way of example include the following: v

In one form of the invention a pressure cylinder unit is shown as embodied in a dead-weight testing apparatus to support a weight of known size in floating relation to a loading pressure to be measured. The weight is mounted on an inside cylinder element freely movable within a vertically arranged sleeve cylinder element. Clearance control pressure is supplied through anV annular cavity or conduit provided between the sleeve cylinder and an encasing jacket cylinder. In order to maintain a free sliding lit between the cylinders the clearance is controlled by adjustment of the clearance control pressure to maintain a controlled leakage of the fluid medium through the unit which is still insuicient to cause excessive loss of loading pressure. A

In another form of the invention a pressure cylinder unit is shown as embodied in a high pressure vessel for testing geological specimens. The inside cylinder takes the form of a piston which projects within the pressure vessel containing a fluid medium maintained at a very high loading pressure. Movement of the piston in combination with controlled variations of the hydraulic loading pressure is utilized to compress and thereafter to release a geological specimen gradually in an axial direction. The amount of clearance between the inside and sleeve cylinder elements is controlledby a manually adjustable clearance control pressure introduced into an'annular .Y cavity or conduit in the sleeve cylinder wall.

In still another form of the invention a pressure cylin- Further inl der unit is employed as a -restrictor valve to maintain a carefully metered flow of fluid medium under high pressure to a reaction which is being carried on also under a high pressure. The sleeve cylinder and inside cylinder elements are maintained in a relatively fixed position axially. A clearance control pressure passing through an annular cavity or conduit formed between the sleeve cylinder and an encasing jacket cylinder acts against the loading pressure within the sleeve cylinder to produce a controlled distortion ofthe sleeve cylinder wall to control the amount of clearance and consequent rate of flow of the fluid medium under pressure through they cylinder unit.

In each of the embodiments ofY the invention thus far referred to the clearance control pressure is applied externally through an annular cavity or conduit extending circumferentially about a jacketed sleeve cylinder element to have a compressive effect thereon offsetting the expansion effect of the loading7 pressure tocontrol the amount of clearance. In accordance with the invention the clearance control pressure may alternatively be applied in such a manner as to effect a controlled expansion of the wall of the inside cylinder of the pressure cylinder unit in order to control the clearance between the inside and sleeve cylinder elements of the unit'.V An illustrative embodiment of this form of the invention in a restrictor valve is shown in which the clearance control pressure is directed into a chamber formed within the inside cylinder and has the effect of expanding the inside cylinder wall to control the rate of flow of the fluid medium through the pressure cylinder unit.

The several features of the invention consisting of the method hereinafter described,'together with the embodiments hereinafter shown and described illustrating preferred forms of the invention, will be readily understood by one skilled in the art from the following description in connection with the accompanying drawings, in which- Fig. 1 is a somewhat diagrammatic view of the deadweight testing apparatus illustrating one embodiment of the invention;

Fig. 2 is a detailed sectional view on an enlarged scale looking in the direction of Fig. 1, of the pressure cylinder unit including the jacketed sleeve cylinder, and the associated inside cylinder or piston on which the testing weights are carried;

Fig. 3 is a sectional view taken on a line 3 3 of Fig. 2 to illustrate particularly the mechanism for continuously rotating the inside cylinder with relation to the sleeve cylinder;

Fig. 4 is a detailed sectional view on a still larger scale of the jacketed sleeve cylinder and inside cylinder elements shown in Fig. 2;

Fig. 5 is a sectional view of a specimen pressure testing device comprising a high pressure vessel within which a geological specimen may be supported and a pressure cylinder unit associated therewith;

Fig. 6 is a sectional view of a restrictor valve comprising a jacketed sleeve cylinder and a relatively stationary inside cylinder or plug, said` jacketed sleeve cylinder having a circumferential conduitV through which a lluid medium is forced under a control pressure for controlling the clearance or orifice of said valve;

Fig. 7 is a sectional View of a restrictor valve comprising a sleeve cylinder element and an inside cylinder element having a chamber into which a fluid medium is forced at a controlled pressure to produce a controlled expansion of the inside cylinder wall against the sleeve cylinder wall; and

Fig. 8 is a sectional view taken on a line 8 8 of Fig. 7.

In each of the several embodiments of the invention illustrated in the drawings and hereinafter more fully described a pressure cylinder unit, comprising metallic sleeve cylinder and inside cylinder elements, is employed, in combination with means for subjecting at least one of said cylinder elements to a control pressure having a force component directed radially to distort the wall of said cylinder element toward the wall of the other of the said elements, and independent means for controlling said control pressure with relation to the internal loading pressure to which the unit is subjected to effect a desired adjustment of the clearance between the elements of the unit and thereby to control the rate of infiltration or leakage of the fluid medium between the elements of the unit. The amount of control pressure applied in each instance is opposed to the internal loading pressure to which the cylinder unit is subjected, the differential between the two pressures being relied upon to effect the desired distortion of the cylinder wall inwardly or outwardly as the case may be. While in the several embodiments shown the adjustment of internal diameter of a sleeve cylinder element is eifected with relation to an associated inside cylinder element, it will be understood that the invention in its broader aspects is not limited to this combination and that a similar adjustment of external diameter of a sleeve cylinder not having the associated inside cylinder can be made if so desired in accordance with the teaching of the invention.

The novel device and method herein disclosed for controlling the amount of clearance and rate of infiltration or leakage between the sleeve cylinder and inside cylinder elements of a pressure cylinder unit has the advantage over pressure cylinder units of the prior art in that it permits of an extremely rapid andaccurate adjustment of the clearance between the cylinder elements under working conditions and at any level of loading pressure to which the unit may be subjected. The device has the further advantage that adjustment is made without the use of any added moving parts, packings or the like.

Referring to the drawings, Figs. l through 4 inclusive illustrate a dead-weight testing apparatus which embodies in a preferred form certain features of the invention. The dead-weight testing apparatus includes a frame consisting of a base plate 24, supporting uprights 22, and a platform 20 on which is mounted a pressure cylinder unit adapted for weighing the pressure to be tested against a known weight. The pressure cylinder unit referred to comprises a sleeve cylinder 26 and an inside cylinder 28 mounted in a bore 29 centrally` located within the sleeve cylinder 26. The sleeve cylinder in turn is supported within a bore 3l formed'in a thick walled jacket cylinder 30 which is screw threaded at its lower end and secured into a threaded aperture 34 formed in the platform 20.

The pressure cylinder unit illustrated for use with the dead-weight testing apparatus is formed with extremely heavy walls and with an inside cylinder of small diameter which is well adapted to withstand loading pressures in the order of 200,000 pounds per square inch. For testing pressures and pressure equipment at lower pressures, pressure cylinder units of different dimensions and having appropriate characteristics of flexibility and the like may be employed.

The sleeve cylinder 26 is connected at its lower end with a supply pipe 38 through which a fluid medium is supplied to the lower end of the pressure cylinder unit under a loading pressure. For convenience of assembly the pipe 38 has threaded to the end thereof a pipe fitting 40 which extendsl within the pressure unit receiving bore 31 of the jacket 30 and is held in place by means of an externally-threaded sleeve nut 42 threaded into the lower end of the jacket bore.` The pipe 38 is connected with the sleeve cylinder 26 by means of a connector 44 having cone-shaped ends which lit into conical seats formed respectively in the ends of pipe 38 and the sleeve cylinder 26. At its upper end the sleeve cylinder 26 is held in place by means of a plug 46 screw threaded into an enlarged upper end of the jacket bore 31.

The inside cylinder element 28 of the pressure cylinder unit is supported and arranged for axial and turning movement within the sleeve cylinder element 26 and is further arranged tosupport the weights which are relied upon in the dead-weight ytesting apparatus to provide an accurate measure of the loading pressure directed against the lower end of the inside cylinder element 28 through the supply pipe 38. As best shown in Figs. 2 and 4 the inside cylinder element 26 is secured at its upper end into a cylindrical member 50 which is connected by means of a tongue and groove connection 52 and a single ball bearing 53 with the lower end of a supporting shaft 54 which extends upwardly through a central bore in the plug 46. The supporting shaft 54 is connected at its upper end by a single ball bearing 56 with a short spindle 58 having a collar 60 on which is mounted a thrust ball bearing 62 providing support for a cross yoke 64, see Fig. 3. For convenience of illustration the yoke 64 is shown with depending straps 66 which pass through apertures in the platform 20, a tray 68 supported by the straps, and a series of scale weights 70 on the tray. Downward movement of the inside cylinder element under the influence of the scale weights 70 is limited by means of a block 72 (see Fig. 3) which is screw threaded to the upper end of the supporting shaft 54 and which is arranged to be supported on the ball bearing 74 mounted on the upper end of the plug 46 when the loading pressure against the bottom end of the inside cylinder element 2S is insufficient to support the weight testing assembly including weights 70.

As best shown in Fig. 3 of the drawings in order to maintain a free sliding lit between the elements of the pressure cylinder unit during the operation of the apparatus, mechanism is provided which is adapted for continuously rotating the supporting shaft 54, cylindrical member 52 and inside cylinder element 28. The mechanism referred to comprises a belt-driven pulley 76 supported to turn 'on a ball bearing 78 fitted onto a slightly reduced portion of the plug 46 and secured in place by a nut 80. The driving pulley 76 is provided at its outer edge with upwardly extending stanchions 82 which are connected by means of light coiled springs 84 with spokes 86 threaded into and extending radially outward from the block 72. The pulley 76 is driven continuously at a slow rate by any convenient means not here shown.

The hydraulic system for supplying a fluid medium at a loading pressure to the pressure cylinder unit of the dead-weight testing apparatus, as best shown in Figs. 1 and 2, comprises the pipe 38 through which fluid pressure is directed into the lower end of the pressure cylinder unit above described. The pipe 38 is connected with an intensilier 90 shown in a somewhat diagrammatic form comprising a casing with bores 92 and 94 of two different diameters and a differential piston 96 having the ends thereof fitted into the respective bores. The bore 94 of the intensifier is connected by means of a pipe 98 with a hand pump100 which may be of ordinary description including a manually operable handle 102 which acts when pumped to force increments of fluid pressure through the pipe 98, intensifier 90, and pipe 38 to the pressure cylinder unit yof the dead-weight testing device. A pressure gauge 104 in the pipe 38 provides a direct reading of the fluid loading pressure directed against the bottom end of the inside cylinder 28. As shown in Fig. l the dead-weight testing apparatus is set up to effect an accurate testing and calibration of the gauge 104.

In accordance with the invention as shown in Figs. 1 to 4 means are provided under the control of the operator for controlling the clearancebetween the inside cylinder and sleeve cylinder elements of the pressure cylinder unit, which will permit the inside cylinder 28 to move freely in response to variations in the balance of loading pressure and weights acting upon the inside cylinder 28 but without excessive loss of the fluid medium and consequent drop in pressure through the pressure -cylinder unit. As shown in Figs. l through 4 an extremely accurate and effective control of the sliding llt between the inside and sleeve elements lof the pressure cylinder unit is obtained by forcing a fluid medium under a control pressure through a circumferential cavity or conduitY provided between the sleeve cylinder element 26 and the jacketing cylinder 30. The value of the control pressure in the circumferential conduit is adapted to be adjusted manually with relation to the value of the loading pressure in the pipe 38 and within the sleeve cylinder element 26 to produce a controlled distortion inwardly of the wall of the sleeve cylinder 26 within the elastic limits of the metal from which the sleeve cylinder is made in orde-r to control the amount of clearance existing between said elements. The circumferential cavity 110 is connected by means of a radial conduit 112 through the jacket cylinder 30,'and a coupling 114 with a pipe 116 which is screw threaded into the side of the jacket cylinder 30. The pipe 116 is connected with an intensifier 118,' comprising a casing formed with two different sized bores 120, 122 and a differential piston 124 with the two ends thereof fitted into said bores. The larger bore 122 of the intensifier is connected by a pipe 126 with a manually operable pump 128 from which increments of the control pressure medium are forced into the circumferential conduit 112 as needed. A gauge 127 tapped into the pipe 116 provides to the operator a direct indication'of the value of the control pressure.

A feature of the invention consists in the novel construction and `arrangement of the sleeve cylinder 26, jacket cylinder 20, and packing devices provided at each side of the circumferential cavity or conduit 110 for sealing in the sides of the cavity to withstand the very high fluid pressures contained within the cavity. Referring specifically to Figs. 2 and 4 it will be noted that the sleeve cylinder 26 is formed with a reduced portion pro* viding external cylindrical surfaces of two different diameters which are connected by a sloping shoulder 129. The internal bore of the jacket cylinder 30 is correspondingly shaped to provide interior cylindrical surfaces which fit tightly over Ithe cylindrical surface of the sleeve cylinder 26 and are similarly connected by a sloping shoulder 131. The two shoulders 129 and 131 are separated from one another to provide a space within whiclh are mounted the packing elements for sealing in the annular cavity 110. The packing elements referred to include a spacer element 130 which is centrally located in a space provided between the shoulders 129, 131 and is loosely fitted to the sleeve cylinder 26 so that a shallow groove is formed between the surface of the sleeve cylinder and the metallic spacer element 130, preferably steel, to form the cavity 110. 'Ilhe cavity 110 is bounded at each side with a hardened steel ring 132, a lead ring 134 and an additional packing ring 136 of mild steel. In order to improve the flow of the fluid medium maintained at the desired control pressure along the annular cavity 110 about the periphery of the sleeve cylinder 26 the spacer band 130 is formed with an external annular groove 137, and with a series of radial holes connecting the groove 137 with tlhe cavity 110.

In order to produce a leak-proof seal with the pack-` ing device above described it is essential to place both ends of the packing under a substantial pressure which will force the mild steel rings 136 against the respective sloping shoulders 129 and 131 to forma pre-seal before the fluid medium under pressure is introduced into the annular cavity 110. With the construction arrangement of the sleeve cylinder and jacket cylinder elements above described, the requisite pre-sealing pressure is obtained simultaneously upon the packings at both sides of the cavity 110 by tightening the plug 46 screw-threaded into the upper end of the jacket cylinder 30, so that the sleeve cylinder 26 is forced downwardly and is telescoped inwardly with relation to the jacket cylinder 30.

The operation of the dead-weight testing apparatus including the pressure cylinder unit with its jacket cylinder 30 will be briefly described as follows: For the purpose of illustration it is supposed that the dead-weight testing apparatus of Fig. 1 has been set up to test the accuracy of the gauge reading of gauge 104 at 200,000

pounds per square inch. It is further assumed that the weights on the tray 68 have been adjusted so that the inside cylinder 28 will float with relation to the sleeve cylinder 26 upon the iluid under pressure directed against the lower end of the inside cylinder when the pressure in conduit 38 has been built up to exactly 200,000 pounds per square inch. It is assumed further that little or no pressure has been applied through cavity 110 which would tend to distort inwardly the wall of the sleeve cylinder 26 so that a relatively large clearance or orifice will exist between the piston 28 and the inner wall of the cylinder 26 which permits the piston to fall under the influence of the weights 70 to a fully depressed position until the yoke 64 and associated parts, including the bearing block 72, are fully supported by the ring ball bearing 74. Fluid pressure is now applied in conduit 38 and in conduit 116 through the operation of the respective hand pumps and 11S until the approximate pressures desired are reached. With the parts shown it may be assumed that the control pressure required in conduit 116 and in the annular cavity 110 for distorting the cylinder wall inwardly will in accordance with the formula PozPiJI-KPi amount to approximately 148,000 pounds per square inch where Pu is the control pressure forced through the circumferential cavity 110, Pi is the internal loading pressure assumed in this example to be 200,000 pounds per square inch. supplied through conduit 33 and K is a constant calculated from the known characteristics of the unit and here assumed to be roughly 64% of P1. 1n order to obtain within close limits the 200,000 pounds per square inch desired in the conduit 38 for an accurate calibration of the dial indicator 104, the clearance or orifice existing in the cylinder should reduce the rate of ow or infiltration of iluid past the piston to an amount which will permit the piston to fall under the influence of its Weight through the full quarter inch extent of its stroke against the pressure to be measured in conduit 38 in approximately one hour. Assuming that the desired condition of pressure in cavity has been obtained, causing the cylinder to be distorted inwardly, pressure is now built up in the conduit 33 against the lower end of the piston 28 until the deadweights 70 are elevated and floating. In order to fully free the piston from any frictional engagement witlh the cylinder, a rotational movement is imparted to the piston 2S by means of the power driven pulley 76 above referred to. An accurate calibration of the gauge 23 may now be made to correspond with the 200,000 pound pressure required in conduit 38 in order to float the piston and weights supported thereby.

My improved high pressure cylinder unit as embodied in the dead-weight testing device above described has made it possible for the rst time with apparatus of this description to secure measurement of very high fluid pressures. An essential element contributing to the satisfactory operation of the dead-weight testing apparatus illustrated consists in the `maintenance of a frictionless sliding fit between the floated inside cylinder or piston element and the sleeve cylinder element of the pressure cylinder unit, but without causing any serious loss of pressure through the unit. I have found that a simple manual adjustment of the externally applied control pressure as above described makes possible a ready adjustment of the clearance between the cylinder walls of my improved unit to within a very few millionhs of an inch to maintain a free sliding fit and at the same time a controlled rate of leakage of the contained fluid pressure medium.

Fig. 5 of the drawings illustrates another form of the invention as embodied in a high pressure vessel for testing geological specimens. The apparatus shown consists of a jacket cylinder having a central bore 142 closed at one end by means of a plug 144 mounted within an enlarged end portion yof the bore and a cap 146 fitted over the end of the cylinder, and closed at its other end by the elements of a pressure cylinder unit comprising a sleeve cylinder element 148 fitted into the bore 142 and held in place by a sleeve member 150 and a cap 152 fitted over the end of the jacket cylinder 140, and an inside cylinder element or piston 154 which is arranged to be moved axially with relation to the sleeve cylinder element 148 by a piston actuating means not shown here. A geological specimen, which may for example be a cylindrically shaped piece of marble is supported between the end of the piston 15d and the projecting end 156 of plug 144, being supported within a thin copper tube 158, which is fitted over the end 156 of the plug and over the piston 154 and which is further spaced inwardly from the interior wall 142 of the jacket cylinder 140. Two cylindrical spacer members 160 and 162 are provided at each end of the specimen for engagement respectively with the piston 154 and projecting end 156 of the plug 144. A fluid medium under pressure is introduced into that portion of the bore 142 in the jacket cylinder 140 which houses the copper tube 15S and enclosed geological specimen in order to prevent radial expansion of the specimen, by means of a radial inlet passageway 164 and a supply pipe 166 through which fluid under pressure is forced by means not specifically shown.

In accordance with the invention the sleeve cylinder 148 is surrounded by a circumferential passageway 163 formed between the sleeve cylinder and jacket cylinder and connected by means of a radial passageway 1'70 and supply pipe 172 with an appropriate means for forcing a fluid medium into the circumferential passageway under a control pressure. The pressure supply means referred to may consist of the intensifier 118 and hand pump 128 conventionally illustrated in Fig. l. In order to prevent leakage from the circumferential passageway 168 between the walls of the sleeve cylinder element 148 and jacket cylinder 140 extensive packing is provided in the form of a number of packing rings generally designated at 174.

ln the operation of the high pressure testing vessel above described, pressure is exerted against the geological specimen axially by the action of piston 154i, and radially by means of a fluid medium which. is forced under pressure into the bore 142 of the jacket cylinder through the radial passageway 164 and supply pipe 166. The pressure applied against the specimen both axially and radially may be in the order of 60,000 pounds per square inch. Under carefully controlled conditions the piston is then slowly Withdrawn causing an elongation of the marble specimen, which may be up to 50% of its initial length.

lt will be understood that as fluid pressure is applied within the bore 142 of the jacket cylinder 140 lluid will tend to escape between the walls of the inside cylinder or piston 154 and the sleeve cylinder 148 and will then drain through a conduit 176 connecting with atmosphere. In order to insure a free sliding t between the inside cylinder and sleeve cylinder elements of the pressure cylinder unit a fluid medium is forced through the circumferential passageway 168 under a control pressure which is sufiicient to distort the wall of the sleeve cylinder inwardly and thereby to control the clearance between the cylinder elements of the unit. The rate of leakage of the lluid medium through the pressure cylinder unit, as indicated by the discharge from the overflow conduit 176, provides a convenient means to the operator for adjusting the control pressure in the circumferential passageway 168 to a value which will produce the required distortion of the sleeve cylinder M8 inwardly to insure a sliding fit between the cylinder elements without excessive pressure loss through the unit.

Fig. 6 of the drawings illustrates another form of the invention as embodied in a restrictor valve for controlling the flow of a fluid medium which is maintained under very high pressure. The restrictor valve shown is intended to supply a fluid at a controlled rate of substantially less than a gallon an hour to a reaction which is taking place under a continuously maintained pressure of 30,000

pounds per square' inch. 'Inthis form of the invention the clearance between the sleeve cylinder and inside cylinder elements of the pressurecylinder unit provides an orifice, the adjustment of whichv is controlled in accordance with the invention by the controlled relative distortion of the elements of the pressure cylinder unit.

The restrictorl valve shown in Fig. 6 comprises a jacket cylinder 180 having a central bore 182 within which is mounted a pressure cylinder unit comprising a sleeve cyl-,

inder 184 and an inside cylinder 186. The sleeve cylinder 184 and inside `cylinder 186 are supported in a relatively stationary position within the jacket cylinder 180 by means of two' plugs 188, l190 fitted into opposite ends of the jacket cylinder and held in place by two externally threaded nuts 192,'194 threaded into the ends of the bore 182. The plugs188 and 190, and nuts 192 and 194 are bored to provide passageways therethrough and to receive the ends of pipes 196, 198 respectively.

In accordance with the invention a circumferential passageway 200 is formed about the sleeve cylinder 184 and internally of the jacket cylinder 180, being connected by means of a radial passageway 202 through the jacket cylinder with a means for forcing a huid medium under a control pressure through the passageway 200. The lluid pressure foncing means may be of any convenient type as for example the hand pump`128, and the intensifier 118 illustrated in Fig. 1. In order to avoid leakage from the circumferential passageway 200 between the walls of the sleeve cylinder 184 and the jacket cylinder 180, an extensive packing is employed in the form of a number of packing rings generally indicated at 204.

The operation of the restrictor Valve shown in Fig. 6 will be described briefly as follows: A fluid medium under pressure is continuously supplied through pipe 196 to one end of the pressure cylinder unit at a high pressure which may be in the order of 35,000 or 40,000 pounds per square inch, and is drawn olf from the other end of the fluid pressure unit through the pipe 198 at a predetermined lower pressure. In the present instance it is contemplated that the pressure in the discharge pipe 19S will be maintained at 30,000 pounds per square inch. The rate of flow of the iluid medium into the discharge pipe 198 is controlled by the size of the clearance or orifice which exists between the elements of the pressure cylinder unit, and which in accordance with the invention is determined by the controlled distortion inwardly of the sleeve cylinder wall. The fluid medium is forced under a control pressure through raidal conduit 202 and passageway 200 in order to control the orifice and thus to maintain an accurately metered flow of iluid through the unit.

Still another form of the invention is shown in Figs. 7 and 8, in which a control pressure under the control of the operator is applied to the elements of the pressure cylinder unit in a manner to produce a controlled expansion of the wall of the inside cylinder, thereby to control the clearance between the inside cylinder and sleeve cylinder elements of the unit. The pressure cylinder unit of Figs. 7 and 8 is employed as a restrictor valve in which the size of the orifice between elements of the pressure cylinder unit is controlled by forcing a fluid medium at a control pressure into the chambered interior of the inside element. The restrictor valve shown in Figs. 7 and 8 comprises a Valve casing 210, which is the sleeve cylinder element of the unit, and a hollowed inside cylinder element or plug which is loosely fitted within the valve casing 210. The casing is formed at one end with an inlet passageway 214 and at the opposite end with an outlet passageway 216. The inside cylinder is formed with a reduced neck portion 218 which extends outwardly through a supporting plug 220 closing one end of the valve casing 210, and is fastened rigidly in position by means of twov check nuts threaded to the outer end of the neck 218. A iluid medium under a control pressure is admitted to the hollowed interior of the inside cylinder element 212 through a bore formedin the neck 218; The fluid medium may be supplied in any conventient way as for'example by use of the hand pump' 100 and intensifier 90 of Fig. 1.

In the operation of the restrictor valve of Figs. 7 and 8 control of the leakage or flow of the fluid medium through the unit between the inlet ypassageway 214 and outlet passageway 216 is controlled by the amount of clearance existing between the sleeve cylinder and insidecylinder elements. In this form of the device as shownin the illustration-of Fig. 6, the rate of flow is readily controlled by an adjustment of the control pressure and consequent expansion of the inside cylinder wall which in turn determines the size of the oriflce between the elements of the unit.

'Ihe invention having being described what is claimedv 1. A pressure cylinder unit arranged to be acted upon by a contained fluid medium at a'loading pressure and connected to exhaust at a lower pressure, which comprises a metallic sleeve cylinder element having a loading pressure inlet and an exhaust pressure outlet, a metallic inside cylinder element'housed within the sleeve cylinder for movement relative to the sleeve cylinder arranged to be acted upon by said contained fluid medium under loading pressure, the adjacent walls of said cylinders being spaced from one another to produce a leakage t clearance therebetween adjustable within the elastic limits of radial expansion and contraction of said cylinder elements and means for applying a control pressure against the wall of at least one of said elements around the entire circumference thereof having a force component directed radially at every point around said circumference tending to distort said wall radially within the elastic limits of said element against the otherY of said elements, and means for varying said controlv pressure with relation to the loading pressure to produce a controlled distortion of said wall and a controlled leakage of said uid pressure medium under loading pressure between the walls of the pressure cylinder elements.

2. A pressure cylinder unit comprising a4 metallic sleeve cylinder element and a metallic inside cylinder elementk housed within'the sleeve cylinder element for movement freely with relation to said sleeve cylinder, the walls of said cylinder elements being spaced from one another to produce a leakage iit clearance therebetween adjustable within the elastic limits of radial expansion and contraction of said cylinder elements, and one of said cylinder elements having a cavity extending circumferentially about the wall of said cylinder element, a supply pressure inlet into the sleeve cylinder element, through which a fluid' medium at a loading pressure is directed past the inside cylinder, a source from which a fluid medium is supplied to said cavity at alcontrol pressure having a radially directed force component tending to distort said wall radially within the elastic limits of said element against the other of said elements, and means for varying said control pressure to produce a controlled distortion of said wall and a controlled leakage of the fluid medium under loading pressure between the walls of the sleeve cylinder and inside cylinder elements to facilitate said free movement of the inside cylinder.

3. A pressure cylinder unit comprising a metallic sleeve cylinder element and a metallic inside cylinder element housed within the sleeve cylinder element, said cylinders being freely movable with relation to one another, the walls of said cylinder elements being spaced from one another to produce a leakage fit therebetween adjustable within the elastic limits of radial expansion and contraction of said cylinder elements, and one of said cylinder elements having in the wall thereof a cavity extending circumferentially of said cylinder element and of narrowr width, a supply pressure inlet into the sleeve cylinder element through which a fluid medium at a loading pressure is directed past the inside cylinder, a source from which a fluid medium is supplied to said cavity at a control pressurehaving a radially directed force component tending to distort a narrow transverse section of said wall radially within the elastic limits of said element against the other of said elements, and means for varying said control pressure to produce a controlled distortion of said wall section and a controlled leakage of the iluid medium under loading pressure, between the walls of.

the sleeve cylinder and inside cylinder elements.

4. A pressure cylinder unit comprising a metallic sleeve cylinder element and a metallic inside cylinder element housed within the sleeve cylinder element for movement axially, the walls of said cylinders being spaced from one another to produce a leakage lit clearance therebetween adjustable within the elastic limits of radial expansion and contraction of said cylinder elements, and said sleeve cylinder element being constructed and :arranged with a cavity extending circumferentially about the wall of the sleeve cylinder element, a supply pressure inlet into the sleeve cylinder element through which a fluid medium at a loading pressure is directed past the inside cylinder, a source 'from which a fluid medium is supplied to said cavity at'a control pressure to exert against the wall of the sleeve cylinder a radially directed force component tending to distort portions of said sleeve cylinder wall adjacent the cavity within the elastic limits of said element against the inside cylinder element, and means for varying the control pressure to control the distortion of said sleeve cylinder wall portions and the leakage of the lluid medium under loading pressure between the walls of the sleeve cylinder and inside cylinder elements and thereby to permit axial movement of said inside cylinder with a minimum loss of said iluid medium at loading pressure.

5. A pressure cylinder unit comprising a metallic sleeve cylinder element and a metallic inside cylinder element housed within the sleeve cylinder element, said cylinders being relatively movable axially, the walls of said cylinder elements being spaced from one another to produce a leakage t clearance therebetween adjustable within the elastic limits of radial expansion and contraction of said cylinder elements, a jacket cylinder itted over the sleeve cylinder element, said sleeve cylinder and jacket cylinder being formed to provide a cavity therebetween extending circumferentially around the sleeve cylinder element, a supply pressure inlet into the sleeve cylinder element through which a fluid medium at a loading pressure is directed past the inside cylinder element, a source from which a fluid medium is supplied at a control pressure to said cavity to exert against the sleeve cylinder wall a radially directed force component tending to distort portions of said wall radially within the elastic limits of said element against the other of said elements, and means for varying said control pressure to produce a controlled distortion of said wall portions and a controlled leakage of the fluid medium under load-ing pressure between the walls of the sleeve cylinder and inside cylinder elements.

6. A pressure cylinder unit comprising a metallic sleeve cylinder element, and a metallic inside cylinder element housed within the sleeve cylinder element for movement axially, the walls of said cylinder elements being spaced from one another to produce a leakage lit clearance therebetween adjustable within the elastic limits of radial expansion and contraction of said metallic cylinder elements, a jacket cylinder fitted over the sleeve cylinder element, said sleeve cylinder and jacket cylinder being constructed and arranged to provide a narrow cavity between said sleeve cylinder element and jacket cylinder extending circumferentially around the sleeve cylinder, a supply inlet and an exhaust outlet into `the sleeve cylinder element at opposite ends of the inside cylinder element, a conduit through which a fluid medium is supplied to the said cavity at a control pressure, and means for varying said control Vpressure for exerting against the sleeve cylinder wall a force component tending to distort adjacent wall portions radially inwardly yand thereby to produce a controlled distortion of said adjacent'wall portions and 'a controlled leakage of the fluid medium betweenthe walls of the sleeve cylinder and inside cylinder elements and thereby to permit axial movement of said inside cylinder with a'minimum loss of said lluid medium at loading pressure.

7. A pressure ycylinder unit comprising a sleeve cylinder element and an inside cylinder element housed and axially movable within the sleeve .cylinder element, the walls of said cylinder elements having a leakage fit therebetween, a jacket cylinder tted over the sleeve cylinder, said sleeve cylinder and jacket cylinder being formed to provide a narrow cavity therebetween extending around a portion of the Wall ofrsaid sleeve cylinder element en'- gaging the inside cylinder element, a supply pressure inlet into the sleeve cylinder element through which a fluid medium is directed past the inside cylinder element, a source from which a uid medium is supplied by a control pressure to said cavity to exert 'against the sleeve cyl-inder wall a radially directedforce component tending to distort said walls radially within the elastic limits of said element against the inside cylinder element, and means for varying said control pressure independently of the loading pressure to produce a controlled distortion of said Walls radially and a controlled leakage of the iiuid medium under loading pressure between the walls of the sleeve cylinder and the inside cylinder elements to facilitate said axial movement of the inside .cylinder element, but with a minimum loss of fluid at loading pressure between said sleeve cylinder and said .inside cylinder elements.

8. For use as a restrictor Valve a pressure cylinder unit comprising a metallic sleeve cylinder element, and a metallic inside cylinder element housed within and supported against axial movement within the sleeve cylinder element, the walls of said cylinder elements being spaced from one another to produce a leakage t clearance therebetween adjustable within the elastic limits of radial expansion and contraction of said cylinder elements, a supply pressure inlet into and an exhaust pressure outlet out of said sleeve cylinder element spaced beyond opposite ends of the inside cylinder element, said sleeve cylinder element being formed with a cavity in the wall thereof extending circumferentially about said wall, a source from which a lluid medium is supplied to said cavity at a control pressure having a radially directed force component tending to distort said wall radially within the elastic limits of said elements against the inside cylinder elements, and means for varying said control pressure independently of said supply pressure to produce a controlled distortion of said wall radially and a controlled leakage of the fluid medium under loading pressure between the walls of the sleeve cy inder and inside cylinder elements.

9. For use as a restrictor valve a pressure cylinder unit comprising a metallic sleeve cylinder element and a metallic inside cylinder element housed within and supported against axial movement within the sleeve cylinder element, the walls of said cylinder elements being spaced from one another to produce a leakage tit clearance therebetween adjustable within the elastic limits of radial expansion and contraction of said cylinder elements, a jacket cylinder fitted over the sleeve cylinder, said sleeve cylinder element and jacket cylinder being formed to provide a cavity therebetween extending circumferentially around the sleeve cylinder element, a supply pressure inlet into and an exhaust outlet from the sleeve cylinder element spaced apart beyond opposite ends of the inside cylinder element, a source from which a fluid medium is supplied at a control pressure to said cavity to exert against the sleeve cylinder wall a radially directed force component tending to distort portions of said wall radially within the elastic limits of said element against the other of said elements, and means for varying said control pressure 13 independently of the supply pressure to produce a controlled distortion of said wall portions radially and a controlled leakage of the fluid medium under loading pressure between the walls of the sleeve cylinder and inside cylinder elements. 5

McClellan Nov. 4, 1919 Mitchell Aug. 23, 1932 10 14 Bigelow Aug. 23, 1932 Grove Apr. 27, 1943 Hornschuch Mar. 27, 1945 Kallam Nov. 6, 1951 Ner Feb. 26, 1952 Sausa Mar. 25, 1952 FOREIGN PATENTS Great Britain of 1941 

